Nanoparticle-based macromolecule drug delivery to lungs

Abstract The pulmonary system is a unique drug delivery system as it offers large surface area, thin layer of epithelia, and higher blood supply ensuring quick absorption of therapeutics. The delivery of pulmonary drugs is relatively complex because the respiratory tract has developed defense mechanisms to keep the inhaled drug particles out of the lungs and to remove or inactivate them once they have been deposited. As a powerful class of drugs for a large number of therapeutic indications, macromolecules have been devised primarily due to their site-specific activities and decreased side effects. This chapter covers macromolecular drugs with liposomes, polymers, dendrimers, and inorganic nanoparticles used in their delivery systems. Unfortunately, numerous challenges, including their large size, limited half-life, phagocytic removal, low membrane permeability, and structural instability, hamper the therapeutic capacity and application of macromolecules. The restrictions of new delivery methods and the potential role of nanotechnology in macromolecular distribution are also discussed. However, processing techniques for nanoformulation are also outlined. Currently the inhalation tools and formulations are in use as targeted approaches at the macroscopic level, but targeting strategies at the micro- and nanoscopic levels are still in the laboratory.